Bedside monitoring of physiological parameters is standard in hospital settings, for example for patients with cardiac diseases. It is also known to measure cardio data or pulmonary data at home. In WO 02/068921 A1, a bed equipped with force sensors and a central monitoring station has been described to monitor basically presence and activity of patients. Novel solutions to this task include mechanical and electrical and electromagnetic sensing of vital parameters using bed-integrated sensors. It is a drawback that these methods are prone to delivering false signals caused by electromagnetic interference (EMI) from the environment. This is especially true for inductive and capacitive measurements.
It is therefore an objective of the invention to provide a sensor arrangement and method for monitoring physiological parameters which is less susceptible to electromagnetic radiation.
The above objective is achieved by a sensor arrangement comprising at least one sensor for monitoring physiological parameters of a person and at least one textile fabric, the textile fabric comprising a conductive shielding for suppressing electromagnetic interference with the sensor.
It is an advantage of the sensor arrangement according to the invention that it allows to integrate an effective shielding into a bed, which reduces noise caused by electromagnetic interference, particularly during measurements using capacitive or inductive sensors or any other method sensitive to electromagnetic interference.
According to a preferred embodiment of the invention, the conductive shielding is connected to a potential equalization. The potential equalization may, in the sense of the embodiment, be an electric potential at which the conductive shielding is actively driven or a grounding. It is an advantage of the sensor arrangement according to this embodiment that static charges or dynamic charges which would disturb capacitive or inductive measurements, may be discharged via the textile fabric. The conductive shielding need not be a closed area, but is preferably composed of a net of conductive elements.
The textile fabric comprising the conductive shielding preferably does not otherwise interfere with daily routines of the person or, for example, hospital personnel. More preferably, it is not obviously visible and/or does not harm the design of a bed or bedroom. Most preferably, the textile fabric, which may be woven or non-woven, is conjoint with a suitable textile, i.e. a textile used in conjunction with a bed.
In a preferred embodiment, the textile fabric is at least part of a wearable garment, in particular of nightwear, like nightgown, pajama etc. According to another preferred embodiment, the textile fabric is integrated in a bed. More preferably, the textile fabric is part of a piece of bedclothes, for example a bed sheet, a pillow case or bed cover. Furthermore preferred, the textile fabric is part of a mattress, which is advantageously stationary, i.e. the mattress cannot be dislocated by the (sleeping) person.
In a further preferred embodiment of the invention, the sensor is integrated in the textile fabric. Advantageously, a plurality of functional elements may be integrated in the textile fabric. More preferably, the textile fabric comprises a layer structure of at least a shielding layer which comprises the conductive shielding, a sensing layer which comprises the sensor and an insulating layer, which is arranged between the shielding layer and the sensing layer. The relative proximity of the sensors to the shielding layer advantageously provides for effective shielding of the sensors.
According to still a further preferred embodiment of the invention, the sensor arrangement further comprises a contact for connecting the person to a potential equalization. Thus advantageously, the body of the person themselves is used as an additional shielding. Further the build up of electrostatic charge due to movements of the person is reduced. The contact is preferably a textile electrode which is, more preferably, arranged in a wearable garment, a bed sheet, a bed cover and/or a pillow.
According to still a further preferred embodiment of the invention, the sensor arrangement comprises two or more textile fabrics, each textile fabric comprising a part of the conductive shielding, wherein the parts of the conductive shielding are electrically connected. It is an advantage of this embodiment that the sensors may be shielded from more than one direction, the conductive shielding preferably surrounding the sensors, thus advantageously forming a kind of Faraday cage.
Preferably, one textile fabric is arranged in a bed cover and the other textile fabric is arranged in a bed sheet or mattress, thus advantageously shielding the sensors from electromagnetic radiation from top and bottom.
Another object of the present invention is a method of monitoring physiological parameters of a person, using at least one wearable or bed-integrated sensor, wherein the sensor is shielded from electromagnetic interference using a textile fabric comprising a conductive shielding. It is an advantage of the method according to the invention that the textile fabric comprising the conductive shielding does not otherwise interfere with daily routines of the person or, for example, the hospital personnel.
Another object of the present invention is a textile fabric with a layer structure comprising at least a sensing layer with at least one sensor, a shielding layer comprising a conductive shielding for suppressing electromagnetic interference with the sensor.
It is an advantage of the textile fabric according to the present invention that a plurality of functional elements is integrated therein. The relative proximity of the sensors to the shielding layer advantageously provides for effective shielding of the sensors. The textile fabric preferably further comprises an insulating layer, the insulating layer being arranged between the shielding layer and the sensing layer.
Another object of the present invention is a use of a textile fabric comprising a conductive shielding for suppressing electromagnetic interference with a bed-integrated or wearable sensor. The use of the textile fabric in connection with bed-integrated or wearable sensors advantageously provides electromagnetic shielding without an undue interference with the daily routines of a person the sensors are allocated to, or, for example, of the hospital personnel.